This invention relates broadly to tools, and more particularly to deburring tools for removing burrs from internal and external surfaces associated with a workpiece.
Burrs are a common problem in machining metal and plastic parts, and are generally formed when a rotating element associated with a machine, e.g. a drill bit, is forced through the part and emerges from the material into an internal cavity or onto an external surface. It is generally desirable to remove burrs from the workpiece. In some applications, however, it is critical that the burrs be removed from the part before the part is incorporated into an assembly. One such application is hydraulic valving. In a hydraulic system, if a burr is not removed from a part before it is incorporated into a valve, it is possible for the burr to break off during operation due to the high fluid pressures and flow within a hydraulic system. The burr can cause significant damage to the hydraulic pump, hoses, valves or associated components.
In addition, another commonly recognized deburring problem involves removing burrs from small holes formed in a part.
It has been known to provide deburring tools which consist of a shank adapted to be received within a rotatable chuck. The deburring tool includes a tip adapted to be inserted into a bore, and abrasive material is provided on the tip. Such tools are available throughout a range of sizes, for use in connection with varying sizes of bores. While deburring tools of this type function satisfactorily, such tools are disadvantageous in that each tool can only be employed for removing burrs within an opening having a diameter corresponding to that of the tool. In addition, such tools have a tendency to roll the burr over rather than remove the burr. Further, deburring tools of this type cannot be satisfactorily made to remove burrs from within small diameter openings.
Accordingly, it is an object of the present invention to provide a deburring tool and method which is suitable for use in removing burrs from within small diameter openings. It is a further object of the invention to provide a single deburring tool which can be used to remove burrs from within bores of varying sizes over a predetermined range, thus reducing the total number of deburring tools needed to remove burrs from within bores having a wide range of sizes. Further, it is an object of the invention to provide a tool which cuts burrs, rather than rolling them over.
In accordance with one aspect of the invention, a tool for removing burrs or other material associated with a circular bore in a workpiece, which is defined by a circular internal side wall, is formed from a first portion which engages the side wall of the bore at a first location, and a second portion which engages the side wall of the bore at a second location, spaced radially from the first location. Abrasive material is provided on at least the second portion of the tool for removing burrs from the bore upon rotation of the tool. The first and second portions of the tool are resiliently interconnected with each other such that engagement of the first portion with the bore side wall at the first location biases the second portion against the bore side wall at the second location. The first and second portions of the tool are preferably formed integrally with each other, and are constructed of a length of wire. In one form of the invention, the first portion of the tool extends along a longitudinal axis oriented parallel to that of the bore when the tool is inserted into the bore. The second portion of the tool is defined by a portion of the length of wire deformed from the longitudinal axis of the first portion. The second portion of the tool can assume varying forms, e.g. a single arcuate section formed in the wire or a double arcuate section in which each section is bent away from the longitudinal axis of the first section to define an elongated oval shape. The abrasive material may take the form of an abrasive coating provided at least on the second portion of the tool, and in some forms of the invention on both the first and second portions of the tool.
With the tool construction as summarized above, burrs can be removed from the internal wall of a bore by inserting the tool within the bore, and rotating the tool about a longitudinal axis parallel to that of the bore, with the abrasive material acting on the burr to dislodge it from the bore side wall. In a form of the invention in which an arcuate section is formed in a single strand of wire, with abrasive material provided on the arcuate section, the tool can be inserted into bores having very small diameters, while nonetheless effectively removing burrs from the internal side wall of the bore.
The resilient interconnection of the first and second portions of the tool allow the tool to be inserted into bores of varying diameters, while providing engagement of the bore side wall by the burr-removing portion of the tool with a force sufficient to remove burrs therefrom upon rotation of the tool.
The invention further contemplates a method of removing burrs from within a bore, substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent upon consideration of the following description taken together with the drawings.